Support : instead of % in transitive dependency exclusion clauses

[Gedochao]

Is your feature request related to a problem? Please describe.
We currently support as-is coursier dependency syntax for excluding transitive dependencies, as per https://scala-cli.virtuslab.org/docs/guides/introduction/dependencies/#excluding-transitive-dependencies.
Because of some internal coursier workarounds, the exclusion syntax cannot use :, and % is used as separator instead.
We could, however, support either by translating with Scala CLI.

Describe the solution you'd like

//> using dep com.lihaoyi::pprint:0.8.1,exclude=com.lihaoyi%%sourcecode

and

//> using dep com.lihaoyi::pprint:0.8.1,exclude=com.lihaoyi::sourcecode

could be equivalents.

cc @prolativ @tgodzik